Introduce MD handle type
As has been previously done for ciphersuites, this commit introduces
a zero-cost abstraction layer around the type
mbedtls_md_info const *
whose valid values represent implementations of message digest algorithms.
Access to a particular digest implementation can be requested by name or
digest ID through the API mbedtls_md_info_from_xxx(), which either returns
a valid implementation or NULL, representing failure.
This commit replaces such uses of `mbedtls_md_info const *` by an abstract
type `mbedtls_md_handle_t` whose valid values represent digest implementations,
and which has a designated invalid value MBEDTLS_MD_INVALID_HANDLE.
The purpose of this abstraction layer is to pave the way for builds which
support precisely one digest algorithm. In this case, mbedtls_md_handle_t
can be implemented as a two-valued type, with one value representing the
invalid handle, and the unique valid value representing the unique enabled
digest.
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index b177779..80f5f16 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -102,12 +102,12 @@
if( cipher_info->mode == MBEDTLS_MODE_CBC ||
cipher_info->mode == MBEDTLS_MODE_STREAM )
{
- mbedtls_md_info_t const *md_info;
+ mbedtls_md_handle_t md_info;
unsigned char *md0, *md1;
/* Pick hash */
md_info = mbedtls_md_info_from_type( hash_id );
- CHK( md_info != NULL );
+ CHK( md_info != MBEDTLS_MD_INVALID_HANDLE );
/* Pick hash keys */
maclen = mbedtls_md_get_size( md_info );